Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To investigate the expressions of c-IAP2 and Smac in leukemia and their prognostic significance in adult patients with acute leukemia (AL), the mRNA expressions of c-IAP2 and Smac in 103 AL adult patients were measured by semi-quantity reverse transcription polymers chain reaction (RT-PCR). Other 20 adults were selected as normal controls (NC), K562 and Kg-1alpha cell lines were employed as positive control. The results showed that the expressions of c-IAP2 and Smac in de novo AL patients were higher than those in NC, while they decreased in patients at complete remission (CR). In relapsed patients, the expressions of c-IAP2 and Smac increased again. The mRNA expression of c-IAP2 and Smac in CML-CP were higher than that of NC, but no statistical significance was found (P > 0.05). In AL patients, the CR rate of c-IAP2+ and Smac+ cases were lower than those of c-IAP2- and Smac- cases. It is concluded that overexpression of c-IAP1 and Smac may play a synergic role in the pathogenesis of AL, and there is a positive correlation beween them. The c-IAP2 and Smac expressions are associated with remission rate in AL, while the patients with high level of c-IAP2 or Smac have low remission rates. It seems that c-IAP2 and Smac serve as markers of poor prognosis in AL.
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PMID:[Expressions of c-IAP2 and Smac gene in leukemia and their clinical significance]. 1663 83

Besides having a pivotal biological function as a component of coenzymes, riboflavin appears a promissing antitumoral agent, but the underlying molecular mechanism remains unclear. In this work, we demonstrate that irradiated riboflavin, when applied at microM concentrations, induces an orderly sequence of signaling events finally leading to leukemia cell death. The molecular mechanism involved is dependent on the activation of caspase 8 caused by overexpression of Fas and FasL and also on mitochondrial amplification mechanisms, involving the stimulation of ceramide production by sphingomyelinase and ceramide synthase. The activation of this cascade led to an inhibition of mitogen activated protein kinases: JNK, MEK and ERK and survival mediators (PKB and IAP1), upregulation of the proapoptotic Bcl2 member Bax and downregulation of cell cycle progression regulators. Importantly, induction of apoptosis by irradiated riboflavin was leukaemia cell specific, as normal human lymphocytes did not respond to the compound with cell death. Our data indicate that riboflavin selectively activates Fas cascade and also constitutes a death receptor-engaged drug without harmful side effects in normal cells, bolstering the case for using this compound as a novel avenue for combating cancerous disease.
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PMID:A promising action of riboflavin as a mediator of leukaemia cell death. 1692 17

Gambogic acid (GA), a xanthone derived from the resin of the Garcinia hanburyi, has been recently demonstrated to bind transferrin receptor and exhibit potential anticancer effects through a signaling mechanism that is not fully understood. Because of the critical role of NF-kappaB signaling pathway, we investigated the effects of GA on NF-kappaB-mediated cellular responses and NF-kappaB-regulated gene products in human leukemia cancer cells. Treatment of cells with GA enhanced apoptosis induced by tumor necrosis factor (TNF) and chemotherapeutic agents, inhibited the expression of gene products involved in antiapoptosis (IAP1 and IAP2, Bcl-2, Bcl-x(L), and TRAF1), proliferation (cyclin D1 and c-Myc), invasion (COX-2 and MMP-9), and angiogenesis (VEGF), all of which are known to be regulated by NF-kappaB. GA suppressed NF-kappaB activation induced by various inflammatory agents and carcinogens and this, accompanied by the inhibition of TAK1/TAB1-mediated IKK activation, inhibited IkappaBalpha phosphorylation and degradation, suppressed p65 phosphorylation and nuclear translocation, and finally abrogated NF-kappaB-dependent reporter gene expression. The NF-kappaB activation induced by TNFR1, TRADD, TRAF2, NIK, TAK1/TAB1, and IKKbeta was also inhibited. The effect of GA mediated through transferrin receptor as down-regulation of the receptor by RNA interference reversed its effects on NF-kappaB and apoptosis. Overall our results demonstrate that GA inhibits NF-kappaB signaling pathway and potentiates apoptosis through its interaction with the transferrin receptor.
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PMID:Gambogic acid, a novel ligand for transferrin receptor, potentiates TNF-induced apoptosis through modulation of the nuclear factor-kappaB signaling pathway. 2364 Sep 97

Imiquimod is an immune response modifier currently used as a topical treatment of genital warts, basal cell carcinoma, cutaneous metastasis of malignant melanoma, and vascular tumors. We developed more efficient killers from the same family of compounds that can induce apoptosis without the prominent pro-inflammatory response associated with imiquimod. Among these new products, tk;4EAPB0203, a member of the imidazo[1,2-a]quinoxalines, exhibits an important cytotoxic activity in vitro. HTLV-I-associated adult T-cell leukemia (ATL) and HTLV-I-negative peripheral T-cell lymphomas are associated with poor prognosis. Using potentially achievable concentrations of EAPB0203, we demonstrate inhibition of cell proliferation, G2/M cell- cycle arrest, and induction of apoptosis in HTLV-I-transformed and HTLV-I-negative malignant T cells and fresh ATL cells, whereas normal resting or activated T lymphocytes were resistant. EAPB0203 treatment significantly down-regulated the antiapoptotic proteins c-IAP-1 and Bcl-XL and resulted in a significant loss of mitochondrial membrane potential, cytoplasmic release of cytochrome c, and caspase-dependent apoptosis. Moreover, in HTLV-I-transformed cells only, EAPB0203 treatment stabilized p21 and p53 proteins but had no effect on NF-kappaB activation. These results support a potential therapeutic role for EAPB0203 in ATL and HTLV-I-negative T-cell lymphomas, either as a systemic or topical therapy for skin lesions.
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PMID:EAPB0203, a member of the imidazoquinoxaline family, inhibits growth and induces caspase-dependent apoptosis in T-cell lymphomas and HTLV-I-associated adult T-cell leukemia/lymphoma. 1821 50

The apoptotic mode of cell death is a major regulatory process in all complex organisms. The low proliferative index and slow accumulation of malignant cells in chronic lymphocytic leukemia (CLL), the most frequent type of leukemia in Europe and North America, suggests that the disease is caused by a defect in apoptosis regulation. Classical apoptosis is executed through the activation of caspases, cysteine proteases which are regulated by a number of pro- and anti-apoptotic proteins. One such checkpoint is the control of caspase activation by a relatively new family of inhibitor of apoptosis proteins (IAPs). They block both the mitochondrial-dependent and -independent apoptotic pathways. The IAP family inhibits apoptosis by binding to specific caspases and possibly by other mechanisms. They also participate in the regulation of cellular and intracellular signal transduction. Six human IAPs have been identified: XIAP, cIAP1, cIAP2, NAIP, livin, and survivin. Because of their important role in regulating apoptosis, IAPs are being investigated as a potential prognostic factor as well as a treatment target in cancer patients. Overexpression of several IAPs has been detected in various hematological malignancies, including acute leukemias, myelodysplastic syndrome (MDS), chronic myeloid leukemia (CML), and many types of lymphoid malignancies, such as chronic lymphocytic leukemia (CLL) and diffuse large B-cell lymphoma (DLBCL). Many publications revealed significant correlation between a high level of IAPs, especially of XIAP and survivin, and tumor progression. It seems that overexpression of XIAP in acute myeloid leukemia (AML) and survivin in acute lymphoblastic leukemia (ALL) and DLBCL could become a new unfavorable prognostic factor. Many studies are now concentrating on evaluating the expression and significance of the other proteins of the IAP family. In this paper the current knowledge of the importance of IAPs in hematological malignancies is presented.
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PMID:[The role of the inhibitor of apoptosis protein (IAP) family in hematological malignancies]. 1828 36

Busulfan (Bu) resistance is a major obstacle to hematopoietic stem cell transplantation (HSCT) of patients with chronic or acute myelogenous leukemia (CML or AML). We used gene expression analysis to identify cellular factors underlying Bu resistance. Two Bu-resistant leukemia cell lines were established, characterized and analyzed for differentially expressed genes. The CML B5/Bu250(6) cells are 4.5-fold more resistant to Bu than their parental B5 cells. The AML KBM3/Bu250(6) cells are 4.0-fold more Bu-resistant than KBM3 parental cells. Both resistant sublines evade Bu-mediated G2-arrest and apoptosis with altered regulations of CHK2 and CDC2 proteins, constitutively up-regulated anti-apoptotic genes (BCL-X(L), BCL2, BCL2L10, BAG3 and IAP2/BIRC3) and down-regulated pro-apoptotic genes (BIK, BNIP3, and LTBR). Bu-induced apoptosis is partly mediated by activation of caspases; use of the inhibitor Z-VAD-FMK completely abrogated PARP1 cleavage and reduced apoptosis by approximately 50%. Furthermore, Bu resistance in these cells may be attributed in part to up-regulation of HSP90 protein and activation of STAT3. The inhibition of HSP90 with geldanamycin attenuated phosphorylated STAT3 and made B5/Bu250(6) and KBM3/Bu250(6) more Bu-sensitive. The analysis of cells derived from patients classified as either clinically resistant or sensitive to high-dose Bu-based chemotherapy indicated alterations in gene expression that were analogous to those observed in the in vitro model cell lines, confirming the potential clinical relevance of this model for Bu resistance.
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PMID:Altered gene expression in busulfan-resistant human myeloid leukemia. 1833 23

Mink cell focus-forming (MCF) murine leukemia viruses (MLVs) are the etiologic agent of thymic lymphoma in mice. We have observed previously that superinfection by MCF13 MLV of certain cell types, such as preleukemic thymic lymphocytes and cultured mink epithelial cells, results in the accumulation of the viral envelope precursor polyprotein, leading to the induction of endoplasmic reticulum (ER) stress. In this study, we demonstrate that the induction of ER stress by MCF13 MLV infection results in an increase in the phosphorylation of the alpha-subunit of eukaryotic initiation factor 2. In cells in which this occurs, we have detected an up-regulation of the cellular inhibitor of apoptosis protein 1 (c-IAP1). The results of real-time RT-PCR quantification of message levels and protein turnover assays indicate that up-regulation of c-IAP1 occurs at the translational level. Elevation of c-IAP1 levels at a posttranscriptional step was detectable in MCF13 MLV-induced thymic lymphomas and chronically infected mink epithelial cells. The ability of a simple retrovirus to regulate cellular gene expression at the translational level may be an important mechanism that contributes to pathogenesis.
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PMID:Up-regulation of a cellular protein at the translational level by a retrovirus. 1837 96

A hallmark of eosinophilic meningoencephalitis is infiltration of leukocytes into brain parenchyma and subarachnoid space infected by Angiostrongylus cantonensis. Apoptosis, a process that eliminates useless cells and counterbalances tissue homeostasis, is important for homeostasis of the immune system. In this study, we investigated the characteristics of cell death induced in BABL/c mice infected with A. cantonensis. We observed increased expression of the apoptotic proteins, caspase-3, caspase-8, caspase-9, and cytochrome c, and decreased expression of anti-apoptotic proteins, B-cell leukemia 2 and inhibitor of apoptosis protein 1. On immunohistochemistry, apoptotic proteins were localized within the leukocytes infiltrate. A terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling assay to detect DNA fragmentation confirmed these observations. The infiltration of leukocytes present in the brain parenchyma and subarachnoid space in vivo may also express these apoptotic regulatory molecules, which demonstrates the capacity of these cells to undergo apoptosis.
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PMID:Apoptosis in meningoencephalitis of Angiostrongylus cantonensis-infected mice. 1847 98

Although pectenotoxin-2 (PTX-2) is known to modify the actin cytoskeleton, very little is known about its apoptosis mechanism. In this study, we investigated whether PTX-2 induces apoptotic effects through suppression of the NF-kappaB signaling pathway in several leukemia cell types. PTX-2 significantly induced growth inhibition and apoptosis in a dose-dependent manner. Treatment with PTX-2 also significantly increased caspase-3 activity and poly (ADP-ribose) polymerase (PARP) cleavage, however caspase-3 inhibitor z-DEVD-fmk significantly inhibited PTX-2-induced cell death. These data suggest that the activation of caspase-3 is associated with PTX-2-induced apoptosis. NF-kappaB has also been shown to inhibit apoptosis in response to chemotherapeutic agents. As examined by the DNA-binding of NF-kappaB activation, we found that PTX-2 suppressed constitutive NF-kappaB activation and determined by p65 and p50 nuclear translocation, and IkappaBalpha degradation through dephosphorylation of Akt. Attenuation of constitutive NF-kappaB activity by pretreatment with pyrrolidine dithiocarbamate (PDTC), an NF-kappaB nuclear translocation inhibitor, induced significantly apoptosis in the presence of PTX-2. In addition, treatment of PTX-2 down-regulated NF-kappaB-dependent gene expression, Cox-2, IAP-1, IAP-2 and XIAP, at the transcriptional and translational level. Taken together, these results suggest that anti-cancer activities induced by PTX-2 may be mediated in part through suppression of constitutive NF-kappaB activity.
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PMID:Pectenotoxin-2 abolishes constitutively activated NF-kappaB, leading to suppression of NF-kappaB related gene products and potentiation of apoptosis. 1860 10

Adult T-cell leukemia (ATL) is a fatal malignancy of T lymphocytes caused by human T-cell leukemia virus type 1 (HTLV-1) infection and remains incurable. Carotenoids are a family of natural pigments and have several biological functions. Among carotenoids, fucoxanthin is known to have antitumorigenic activity, but the precise mechanism of action is not elucidated. We evaluated the anti-ATL effects of fucoxanthin and its metabolite, fucoxanthinol. Both carotenoids inhibited cell viability of HTLV-1-infected T-cell lines and ATL cells, and fucoxanthinol was approximately twice more potent than fucoxanthin. In contrast, other carotenoids, beta-carotene and astaxanthin, had mild inhibitory effects on HTLV-1-infected T-cell lines. Importantly, uninfected cell lines and normal peripheral blood mononuclear cells were resistant to fucoxanthin and fucoxanthinol. Both carotenoids induced cell cycle arrest during G(1) phase by reducing the expression of cyclin D1, cyclin D2, CDK4 and CDK6, and inducing the expression of GADD45alpha, and induced apoptosis by reducing the expression of Bcl-2, XIAP, cIAP2 and survivin. The induced apoptosis was associated with activation of caspase-3, -8 and -9. Fucoxanthin and fucoxanthinol also suppressed IkappaBalpha phosphorylation and JunD expression, resulting in inactivation of nuclear factor-kappaB and activator protein-1. Mice with severe combined immunodeficiency harboring tumors induced by inoculation of HTLV-1-infected T cells responded to treatment with fucoxanthinol with suppression of tumor growth, showed extensive tissue distribution of fucoxanthinol, and the presence of therapeutically effective serum concentrations of fucoxanthinol. Our preclinical data suggest that fucoxanthin and fucoxanthinol could be potentially useful therapeutic agents for patients with ATL.
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PMID:Anti-adult T-cell leukemia effects of brown algae fucoxanthin and its deacetylated product, fucoxanthinol. 1879 63


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